An electric motor is typically either air cooled or liquid cooled. An air cooled electric motor will typically have air blown over a stator core and wire windings. In this arrangement, the electric motor can be referred to as a non-sealed or open motor such that air is able to blow through the stator core and over the windings. In a closed or sealed motor, air is typically blown across cooling fins on an exterior case of the motor to dissipate waste heat from the motor. In either the non-sealed or the sealed motor, air-cooling provides less complex but relatively inefficient cooling of the electric motor as compared to liquid cooling.
A liquid-cooled electric motor typically has an annular jacket positioned between an outside diameter of the stator core and an inside diameter of the exterior case. Water is circulated through the jacket and around the stator core to remove heat that is produced in the stator core and in the stator windings. Traditionally, the jacket is located relatively far from the winding end-turns. It can be appreciated that heat generated in the winding end-turns travels through the windings and stator core to be extracted by the jacket. The thermal path from the winding end-turns through portions of the stator core to the liquid jacket typically includes many materials with low thermal conductivity, which can reduce cooling to the winding end-turns.